The present invention relates to a signal receiving and a signal transmitting unit adapted to receive and further transmit an information-carrying signal with no change in the information content of the signal.
The invention particularly relates to converting an information-carrying signal received at a first transmission rate to an information-carrying signal which is transmitted at a second transmission rate with the same information content as the received signal.
Several different kinds of signal receiving and signal transmitting units of the aforesaid kind are known to the art.
Different principles of converting the transmission rates of signals through switches and like devices are known and applied in the telecommunications field.
It is also known, and standard, to use different transmission rates, such as 155 Mb/s and 622 Mb/s and also other transmission rates, such as 2.5 Gb/s, for instance.
Also known to the art are multiplexing signal receiving and signal transmitting units in which signals received on a connection have a signal transmission rate of 155 Mb/s and are converted to a connection transmitted signal having a transmission rate of 622 Mb/s.
Similar units are also known in which this rate conversion can be effected from 155 Mb/s to 2.5 Gb/s.
Also known to the art are demultiplexing units in which the signal transmission rate is converted from 622 Mb/s to 155 Mb/s, and so on.
Units of this kind are also known for conversion of other signal transmission rates.
Normally, such units are adapted for one single conversion index and each desired rate conversion requires a unit which corresponds to the chosen rate conversion.
Consequently, several such units are required for different purposes within switching equipment and other types of electronic equipment.
With regard to the present invention and to its particular application, it can be mentioned that a signalling pattern is known in which information-carrying data packets, such as ATM cells, are transmitted, either in series or in parallel, on each of a number of available connections.
A signalling pattern is also known in which a number of available lines are adapted to the number of bit positions in a word within a data packet, such as an ATM cell, and the signal on each of these lines is permitted to carry the content of respective bit positions simultaneously, wherein a number of instantaneous bit positions occurring on these lines together represent the signal information of a data word.
The present invention can be applied advantageously in a system described in Ericsson Review No. 1, 1993, in the articles "The ATM Switch Concept and The ATM Pipe Switch" by Mikael Larsson, et al, and "The Telecom Evolution in the Broadband Era" by Peter Staxen, et al.